JP6948444B2 - Adhesive composition - Google Patents

Description

The present invention relates to an adhesive composition.

In recent years, due to growing social interest in the environment and safety, there is an increasing need for products that save energy and reduce carbon dioxide. Especially in the field of transportation equipment such as automobiles and aircraft, attempts are being made to reduce the weight of the vehicle body in order to improve fuel efficiency. It is necessary to maintain high rigidity while reducing the weight of the vehicle body by using aluminum, carbon fiber composite material, or the like instead of the conventional steel plate. In order to reduce the weight, it is necessary to use various lightweight base materials in combination, and it is necessary to increase the strength and rigidity of the joint portion, that is, to maintain the strength of the adhesive joint portion to be high. In an automobile, in order to maintain high rigidity, strength, etc. of a vehicle body, the adhesive used is required to have high adhesiveness to a steel plate even at a high temperature. For example, Patent Document 1 proposes using a resin composition containing cellulose nanofibers as an adhesive.

Japanese Unexamined Patent Publication No. 2016-138220

Since the cellulose nanofibers described in Patent Document 1 are only mechanically defibrated from hydrophilic cellulose and are not oil-conditioned, the cellulose nanofibers aggregate in the resin. Therefore, the heat resistance of the resin cannot be improved as much as expected. An object of the present invention is to provide an adhesive composition having heat resistance and high adhesiveness by uniformly dispersing fine fibrous cellulose in a resin by converting cellulose fibers into oil.

The present inventors have solved the above problems with an adhesive composition characterized by containing fine fibrous cellulose and a matrix resin.
That is, it is an object of the present invention to provide the following [1] to [6].
[1] An adhesive composition containing fine fibrous cellulose and a matrix resin satisfying the following conditions (A) to (E).
(A) Number average fiber diameter is 2 nm or more and 500 nm or less (B) Average aspect ratio is 10 or more and 1000 or less (C) Cellulose I-type crystal structure (D) Anionic functional group (E) (D). A polyether amine represented by the following formula (1) is bonded to a part or all of the anionic functional groups.

〔上記式（１）中、Ｒ^１、Ｒ^２、Ｒ^３は炭素数１以上２０以下の直鎖もしくは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ｎ1、ｎ2、ｎ3はそれぞれ０以上８０以下を示し、（ｎ1＋ｎ2＋ｎ3）は１０以上２４０以下を示し、ＡＯは炭素数２以上４以下のオキシアルキレン基を示し、xの平均値は０．５以上１以下、
ｙ、ｚの平均値は０以上１以下を示す。〕
[２]上記微細繊維状セルロースがさらに下記条件を満たすことを特徴とする[１]に記載
の接着剤組成物。
（F）（D）記載のアニオン性官能基の一部、または全てに上記一般式（１）で示すポリエーテルアミンと下記一般式（２）で示すアミン化合物が結合している。

[In the above formula (1), R ¹ , R ² , and R ³ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and n1, n2 and n3 each indicate 0 or more and 80 or less, (n1 + n2 + n3) indicates 10 or more and 240 or less, AO indicates an oxyalkylene group having 2 or more and 4 or less carbon atoms, and the average value of x is 0.5 or more and 1 or less.
The average value of y and z indicates 0 or more and 1 or less. ]
[2] The adhesive composition according to [1], wherein the fine fibrous cellulose further satisfies the following conditions.
(F) A polyether amine represented by the above general formula (1) and an amine compound represented by the following general formula (2) are bonded to a part or all of the anionic functional groups described in (D).

〔上記式（２）中、Ｒ^４、Ｒ^５、Ｒ^６は炭素数１以上２０以下の直鎖あるいは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示す。〕
[３]上記微細繊維状セルロースのアニオン性官能基がカルボキシル基であることを特徴とする[１]または[２]記載の接着剤組成物。
[４]上記マトリクス樹脂が、重縮合系樹脂、重付加重合系樹脂、付加縮合系樹脂、および付加重合系樹脂から選択される、１種又は２種以上であることを特徴とする[１]ないし[
３]のいずれか１に記載の接着剤組成物。
[５]上記マトリクス樹脂が、エポキシ樹脂、ウレタン樹脂、アクリル系樹脂、酸ビニル系樹脂、および炭化水素系樹脂を含有することを特徴とする請求項[１]ないし[４]のいずれか１項に記載の接着剤組成物。
[６]上記微細繊維状セルロースの固形分含有量が０．０５質量％以上３．０質量％以下の範囲であることを特徴とする［１］ないし［５］のいずれか一に記載の接着剤組成物。

[In the above formula (2), R ⁴ , R ⁵ , and R ⁶ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom. ]
[3] The adhesive composition according to [1] or [2], wherein the anionic functional group of the fine fibrous cellulose is a carboxyl group.
[4] The matrix resin is one or more selected from polycondensation resin, polyaddition polymerization resin, addition condensation resin, and addition polymerization resin [1]. Or [
3] The adhesive composition according to any one of.
[5] Any one of claims [1] to [4], wherein the matrix resin contains an epoxy resin, a urethane resin, an acrylic resin, a vinyl acid acid resin, and a hydrocarbon resin. The adhesive composition according to.
[6] The adhesion according to any one of [1] to [5], wherein the solid content of the fine fibrous cellulose is in the range of 0.05% by mass or more and 3.0% by mass or less. Agent composition.

The adhesive composition of the present invention has heat resistance and high adhesive strength.

The adhesive composition of the present invention contains a predetermined fine fibrous cellulose and a resin.

[Fine fibrous cellulose]
The fine fibrous cellulose satisfies the following conditions.

<Average fiber diameter>
The number average fiber diameter of the fine fibrous cellulose is 2 nm or more and 500 nm or less, preferably 2 nm or more and 150 nm or less, more preferably 2 nm or more and 100 nm or less, and particularly preferably 3 nm or more and 80 nm or less. If the number average fiber diameter is less than 2 nm, the crystal structure of the fine fibrous cellulose may be lost and the adhesive strength may not be improved. Even if the number average fiber diameter exceeds 500 nm, the fine fibrous cellulose is an adhesive. May settle in the composition. The maximum fiber diameter is preferably 1000 nm or less, and particularly preferably 500 nm or less, in terms of dispersibility of the fine fibrous cellulose.

The number average fiber diameter and the maximum fiber diameter of the fine fibrous cellulose can be measured, for example, as follows. That is, an aqueous dispersion of fine cellulose having a solid content of 0.05 to 0.1% by weight was prepared, and the dispersion was cast on a carbon film-coated grid having been hydrophilized, and a transmission electron microscope was used. (TEM) observation sample. When fibers having a large fiber diameter are included, a scanning electron microscope (SEM) image of the surface cast on the glass may be observed. Then, observation is performed using an electron microscope image at a magnification of 5000 times, 10000 times, or 50,000 times depending on the size of the constituent fibers. At that time, an axis having an arbitrary vertical and horizontal image width is assumed in the obtained image, and the sample and observation conditions (magnification, etc.) are adjusted so that 20 or more fibers intersect the axis. Then, after obtaining an observation image satisfying this condition, two random axes in each of the vertical and horizontal directions are drawn with respect to this image, and the fiber diameters of the fibers intersecting the axes are visually read. In this way, images of at least three non-overlapping surface portions are taken with an electron microscope and the value of the fiber diameter of the fibers intersecting each of the two axes is read (thus, at least 20 fibers × 2 × 3 = 120). Information on the fiber diameter of the book can be obtained). From the fiber diameter data obtained in this way, the maximum fiber diameter and the number average fiber diameter are calculated.

<Average aspect ratio>
The average aspect ratio of the fine fibrous cellulose is 10 or more and 1000 or less, preferably 100 or more, and more preferably 200 or more. If the average aspect ratio is less than 10, the surface charge is reduced and fine fibrous cellulose may aggregate in the adhesive composition.

The average aspect ratio of the fine fibrous cellulose can be measured by, for example, the following method, that is, the number average fiber diameter and the fiber length are calculated according to the method described above, and the average is averaged using these values. The aspect ratio was calculated according to the following formula.

<Cellulose type I crystal structure>
The fine fibrous cellulose is a fiber obtained by refining a naturally-derived cellulose raw material having an I-type crystal structure. That is, in the process of biosynthesis of natural cellulose, nanofibers called microfibrils are first formed almost without exception, and these are multi-bundle to form a high-order solid structure.
The fact that the cellulose constituting the fine fibrous cellulose has an I-type crystal structure means that, for example, in the diffraction profile obtained by wide-angle X-ray diffraction image measurement, 2 theta = 14 to 17 ° and 2 theta = 22 to 23. It can be identified by having typical peaks at two positions near °.

<Anionic functional group>
The fine fibrous cellulose has an anionic functional group.

The anionic functional group of the present invention is not particularly limited, and specific examples thereof include a carboxyl group, a phosphoric acid group, and a sulfate group. Among these, the reason is that the anionic functional group can be easily introduced into cellulose. Therefore, a carboxyl group is preferable.

As a method for introducing a carboxyl group into cellulose, a method of reacting at least one selected from the group consisting of a compound having a carboxyl group at the hydroxyl group of cellulose, an acid anhydride of a compound having a carboxyl group, and a derivative thereof, Examples thereof include a method of converting a hydroxyl group into a carboxyl group by oxidizing the hydroxyl group.

The compound having a carboxyl group is not particularly limited, and specific examples thereof include acetic acid halide, and acetic acid halide includes chloroacetic acid, bromoacetic acid, iodoacetic acid and the like.

The acid anhydride of the compound having a carboxyl group is not particularly limited, but an acid anhydride of a dicarboxylic acid compound such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride can be used. Can be mentioned.

The derivative of the compound having a carboxyl group is not particularly limited, and examples thereof include an imide of an acid anhydride of a compound having a carboxyl group and a derivative of an acid anhydride of a compound having a carboxyl group.

The imide of the acid anhydride of the compound having a carboxyl group is not particularly limited, and examples thereof include an imide of a dicarboxylic acid compound such as maleimide, succinateimide, and phthalateimide.

The derivative of the acid anhydride of the compound having a carboxyl group is not particularly limited, but at least one of the acid anhydrides of the compound having a carboxyl group such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride and the like. Examples thereof include those in which the hydrogen atom of the portion is substituted with a substituent (for example, an alkyl group, a phenyl group, etc.).

The method for oxidizing the hydroxyl group of cellulose is not particularly limited, and specific examples thereof include a method in which an N-oxyl compound is used as an oxidation catalyst and an copolymer is allowed to act on it.

In the present invention, as a method for introducing a carboxyl group into cellulose, a method of oxidizing the hydroxyl group of cellulose is preferable because the selectivity of the hydroxyl group on the fiber surface is excellent and the reaction conditions are mild. Hereinafter, cellulose having a carboxyl group introduced by oxidation of a hydroxyl group is referred to as cellulose oxide.

Moreover, as a method of introducing a phosphoric acid group into cellulose as one embodiment, the following method can be mentioned. That is, a method of mixing a powder or an aqueous solution of phosphoric acid or a phosphoric acid derivative with a dry or wet cellulose fiber raw material, a method of adding an aqueous solution of phosphoric acid or a phosphoric acid derivative to a dispersion liquid of a cellulose fiber raw material, and the like can be mentioned. Be done. In these methods, usually, after mixing or adding a powder or an aqueous solution of phosphoric acid or a phosphoric acid derivative, dehydration treatment, heat treatment and the like are performed. Here, examples of the phosphoric acid or the phosphoric acid derivative include at least one compound selected from oxo acids containing a phosphorus atom, polyoxo acids, and derivatives thereof. As a result, a compound containing a phosphoric acid group or a salt thereof is dehydrated at the hydroxyl group of the glucose unit constituting cellulose to form a phosphoric acid ester, and the phosphoric acid group or a salt thereof is introduced.

The content of the anionic functional group of the fine fibrous cellulose of the present invention is preferably in the range of 0.5 mmol / g or more and 2.5 mmol / g or less, more preferably 1.5 mmol / g, from the viewpoint of dispersion stability of the fine fibrous cellulose. It is in the range of g or more and 2.0 mmol / g or less.

The amount of anionic functional group of the fine fibrous cellulose is measured by the following method, for example, when the anionic functional group is a carboxyl group. That is, 60 ml of a 0.5 to 1 wt% slurry was prepared from a cellulose sample whose dry weight was precisely weighed, the pH was adjusted to about 2.5 with a 0.1 M hydrochloric acid aqueous solution, and then a 0.05 M sodium hydroxide aqueous solution was added. Drop it and measure the electrical conductivity. The measurement is continued until the pH reaches about 11. From the amount of sodium hydroxide (V) consumed in the neutralization step of a weak acid whose electrical conductivity changes slowly, the amount of carboxyl groups can be determined according to the following formula (2).

The amount of the anionic functional group of the fine fibrous cellulose is measured by the following method, for example, when the anionic functional group is a carboxylmethyl group. That is, the fine fibrous cellulose is prepared in a 0.6 mass% slurry, a 0.1 M hydrochloric acid aqueous solution is added to adjust the pH to 2.4, and then a 0.05 N sodium hydroxide aqueous solution is added dropwise to bring the pH to 11. The amount of carboxyl groups can be measured from the amount of sodium hydroxide consumed in the neutralization stage of a weak acid whose electrical conductivity changes slowly, and can be calculated using the following formula.

<Polyether amine>
Fine fibrous cellulose is formed by binding a polyether amine. Cellulose fibers are dispersed and stabilized in a matrix resin and a solvent by surface-modifying them with polyether amines.

In the above formula (1), R ¹ , R ² , and R ³ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and are n1, n2. , N3 indicate 0 or more and 80 or less, (n1 + n2 + n3) indicates 10 or more and 240 or less, AO indicates an oxyalkylene group having 2 or more and 4 or less carbon atoms, and the average value of x is 0.5 or more and 1 or less.
The average value of y and z indicates 0 or more and 1 or less. The above-mentioned R ¹ , R ² and R ³ are preferably an alkyl group having 1 or more and 10 or less carbon atoms, and more preferably an alkyl group having 1 or more and 3 or less carbon atoms. Further, AO is preferably an oxyalkylene group having 2 carbon atoms, and n1, n2 and n3 are 20 or more and 8 respectively.
It is preferably 0 or less, and (n1 + n2 + n3) is preferably 20 or more and 160 or less, 2
More preferably, it is 0 or more and 80 or less. It is preferable that the average value of x is 0.8 or more and 1 or less, and the average value of y and z is 0 or more and 0.2 or less.

Examples of the polyether amine that can be preferably used in the present invention include the following formula (i):

〔式中、Ｒ^ａは炭素数１以上２０以下の直鎖もしくは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ＥＯ及びＰＯはランダム又はブロック状に存在し、ａはＥＯの平均付加モル数を示す正の数、ｂはＰＯの平均付加モル数を示す正の数であり、ａ、ｂはそれぞれ０以上８０以下が好ましく、ａ＋ｂは１０以上８０以下であり、好ましくは２０以上８０以下である〕があげられる。

[In the formula, Ra represents ^a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and EO and PO are present in a random or block form. a is a positive number indicating the average number of added moles of EO, b is a positive number indicating the average number of added moles of PO, a and b are preferably 0 or more and 80 or less, respectively, and a + b is 10 or more and 80 or less. , Preferably 20 or more and 80 or less].

Examples of the polyether amines that can be preferably used in commercial products include Jeffamine M-2070, Jeffamine M-2005, Jeffamine M-1000, Jeffamine M-2095, Jeffamine M-3085, XTJ-436, and BASF manufactured by HUNTSMAN. Made by Polyetheramine D 2
000 etc. can be given.

Further, examples of the polyether amine that can be preferably used in the present invention include the following formula (ii):

〔式中、Ｒ^ｂ、Ｒ^ｃは炭素数１以上２０以下の直鎖または分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ＥＯ及びＰＯはランダム又はブロック状に存在し、ｃおよびｅはＥＯの平均付加モル数を示し、ｄおよびｆはＰＯの平均付加モル数を示し、ｃ、ｄ、ｅ、ｆはそれぞれ０以上８０以下であり、ｃ＋ｄおよびｅ＋ｆは１０以上１６０以下であり、好ましくは２０以上８０以下である〕
下記式（iii）

[In the formula, R ^b and R ^c represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and EO and PO are in a random or block form. Exist, c and e indicate the average number of added moles of EO, d and f indicate the average number of added moles of PO, c, d, e and f are 0 or more and 80 or less, respectively, and c + d and e + f are 10. More than 160, preferably 20 or more and 80 or less]
The following formula (iii)

〔式中、Ｒ^ｄ、Ｒ^ｅ、Ｒ^ｆは炭素数１以上２０以下の直鎖あるいは分岐のアルキレン基、炭素数１以上２０以下のアリーレン基、または水素原子を示し、ＥＯ及びＰＯはランダム又はブロック状に存在し、ｇ、ｉおよびｋはＥＯの平均付加モル数を示し、ｈ、ｊおよびｌはＰＯの平均付加モル数を示し、ｇ、ｈ、ｉ、ｊ、ｋ、およびｌはそれぞれ０以上８０以下であり、ｇ＋ｈ、ｉ＋ｊ、およびｋ＋ｌはそれぞれ１０以上２４０以下であり、好ましくは２０以上１６０以下であり、より好ましくは２０以上８０以下である〕で表される化合物があげられる。

[In the formula, R ^d , ^Re , R ^f represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom, and EO and PO are random or Existing in blocks, g, i and k indicate the average number of moles added of EO, h, j and l indicate the average number of moles added of PO, and g, h, i, j, k, and l respectively. 0 or more and 80 or less, g + h, i + j, and k + l are 10 or more and 240 or less, respectively, preferably 20 or more and 160 or less, and more preferably 20 or more and 80 or less].

The fine fibrous cellulose of the present invention may have only one type of the above-mentioned polyether amine, or may have two or more types of the above-mentioned polyether amine.

<Amine compound>
When a part of the anionic group of the fine fibrous cellulose is bonded to the polyether amine, the amine compound represented by the following general formula (2) may be bonded to the remaining anionic group.

In the above formula (2), R ⁴ , R ⁵ , and R ⁶ represent a linear or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 1 to 20 carbon atoms, or a hydrogen atom.

The above-mentioned R ⁴ , R ⁵ , and R ⁶ are preferably an alkyl group having 2 or more and 18 or less carbon atoms, and more preferably an alkyl group having 2 or more and 8 or less carbon atoms.

The amine compound represented by the above formula (2) is not particularly limited, but for example, propylamine, butylamine, hexylamine, cyclohexylamine, octylamine, decylamine, hexadecylamine, octadecylamine, ethanolamine, benzylamine and the like. Secondary amines such as primary amines, dimethylamines, diethylamines, diisopropylamines, diallylamines, dioctadecylamines, methylethylamines, tertiary butylethylamines, diethanolamines, dibenzylamines, triethylamines, triisopropylamines, tributylamines, trioctyls. Tertiary amines such as amines, dimethylbutylamines, dimethyloctylamines, dimethyldecylamines, dimethyloctadecylamines, dimethylbenzylamines, diethylmethylamines, dioctadecylmethylamines, triethanolamines, triisopropanolamines, lauryldiethanolamines, tribenzylamines, etc. Can be given. Of these, propylamine, butylamine, hexylamine, octylamine, decylamine, hexadecylamine, octadecylamine, ethanolamine, dimethylamine, diethylamine, diisopropylamine, diallylamine, dioctadecylamine, methylethylamine, tertiary butylethylamine, diethanolamine. , Triethylamine, triisopropylamine, tributylamine, trioctylamine, dimethylbutylamine, dimethyloctylamine, dimethyldecylamine, dimethyloctadecylamine, dimethylbenzylamine, diethylmethylamine, dioctadecylmethylamine, triethanolamine, triisopropanolamine, Lauryl diethanolamine is preferable, and triethylamine, triisopropylamine, tributylamine, trioctylamine, dimethylbutylamine, dimethyloctylamine, dimethyldecylamine, dimethyloctadecylamine, dimethylbenzylamine, diethylmethylamine, and dioctadecylmethylamine are more preferable.

When the above-mentioned polyether amine and the amine compound are used in combination, the blending ratio is a molar ratio of the polyether amine / amine compound = 99/1 to 25/75 in terms of the dispersibility of the fine fibrous cellulose and the adhesive strength of the adhesive composition. Is preferable, and 50/50 to 25/75 is more preferable.

[Manufacturing method of fine fibrous cellulose]
The fine fibrous cellulose of the present invention is preferable because it can be produced more efficiently according to the production method having the following steps (1) to (4).
Step (1): After dispersing the cellulose fiber having a cellulose type I crystal structure in water, the hydroxyl group of the cellulose fiber is converted into a substituent having a carboxyl group. Step (2): Dispersion medium of the cellulose fiber Step (3): Step of adding polyetheramine to the cellulose fiber after the dispersion medium replacement (4): Step of replacing the cellulose fiber to which the polyetheramine is bound in the organic solvent. Nano-fibering process

<Process (1)>
The step (1) is a step of converting the hydroxyl group of cellulose having a cellulose type I crystal structure into a substituent having a carboxyl group (carboxyl group, carboxyl base, carboxylalkyl group, etc.) by oxidation or the like.

Cellulose As the cellulose having a type I crystal structure, natural cellulose is usually used. Here, the natural cellulose means purified cellulose isolated from the biosynthetic system of cellulose such as plants, animals, and bacterial gels. More specifically, softwood pulp, broadleaf pulp, cotton linter, cotton lint and other cotton pulp, straw pulp, bagas pulp and other non-wood pulp, bacterial cellulose (BC), cellulose isolated from squirrel, seaweed. Examples thereof include cellulose isolated from. Of these, softwood pulp, hardwood pulp, cotton linter, cotton lint and other cotton pulp, and straw pulp, bagas pulp and other non-wood pulp are preferable. It is preferable that the natural cellulose is subjected to a treatment for increasing the surface area such as beating because the reaction efficiency can be increased and the productivity can be increased.

The fact that cellulose has an I-type crystal structure means that, for example, in the diffraction profile obtained by wide-angle X-ray diffraction image measurement, 2 theta = 14 to 17 ° and 2 theta = 22 to 23 °.
It can be identified by having typical peaks at two nearby positions.

Examples of the cellulose in which the hydroxyl group on the surface of the cellulose fiber is converted into a substituent having a carboxyl group include oxidized cellulose, carboxymethyl cellulose, polyvalent carboxymethyl cellulose, or a salt thereof. Of these, cellulose oxide using an N-oxyl compound as an oxidizing agent, which has excellent selectivity of hydroxyl groups on the fiber surface and mild reaction conditions, is preferable.

As described above, a method for obtaining oxidized cellulose by using an N-oxyl compound which can be more preferably selected from the fine fibrous cellulose having a carboxyl group of the present invention as an oxidizing agent will be described in detail below.

(Oxidation process)
The oxidized cellulose is subjected to an oxidation treatment in the presence of the natural cellulose, an N-oxyl compound and an copolymer to obtain a cellulose fiber containing a carboxy group.

The dispersion medium of cellulose in the oxidation reaction is water, and the concentration of cellulose in the reaction aqueous solution is arbitrary as long as the concentration allows sufficient diffusion of cellulose. Normally, it is about 5% or less based on the weight of the reaction aqueous solution, but the reaction concentration can be increased by using an apparatus having a strong mechanical stirring force.

Examples of the N-oxyl compound include compounds having a nitrox radical, which is generally used as an oxidation catalyst. The N-oxyl compound is preferably a water-soluble compound, particularly preferably a piperidine nitroxyoxy radical, particularly 2,2,6,6-tetramethylpiperidinooxy radical or 4-acetamido-2,2. 6,6-Tetramethylpiperidinooxy radicals are preferred. The amount of the catalyst is sufficient for the addition of the N-oxyl compound, and the N-oxyl compound is preferably added to the reaction aqueous solution in the range of 0.1 to 4 mmol / l, more preferably 0.2 to 2 mmol / l.

The cooxidant is not a substance that directly oxidizes the hydroxyl group of cellulose, but a substance that oxidizes an N-oxyl compound used as an oxidation catalyst. Examples thereof include hypohalous acid or a salt thereof, hypohalogenic acid or a salt thereof, perhalogenic acid or a salt thereof, hydrogen peroxide, a perorganic acid and the like. These may be used alone or in combination of two or more. Of these, alkali metal hypohalites such as sodium hypochlorite and sodium hypobromite are preferable. When the sodium hypochlorite is used, it is preferable to proceed the reaction in the presence of an alkali metal bromide such as sodium bromide in terms of reaction rate. The amount of the alkali metal bromide added is about 1 to 40 times the molar amount, preferably about 10 to 20 times the molar amount of the N-oxyl compound.

The pH of the reaction aqueous solution is preferably maintained in the range of about 8 to 11. The temperature of the aqueous solution is arbitrary at about 4 to 40 ° C., but the reaction can be carried out at room temperature (25 ° C.), and no particular temperature control is required.

In order to obtain the desired amount of carboxyl groups and the like, the degree of oxidation is controlled by the amount of the copolymer added and the reaction time.

(Reduction process)
The cellulose fibers after the oxidation treatment are preferably reduced with a reducing agent. As a result, some or all of the aldehyde group and the ketone group are reduced and returned to the hydroxyl group. The carboxyl group is not reduced. The total content of the carbonyl groups (aldehyde group and ketone group) calculated by the semicarbazide method described later in the oxidized cellulose by the reduction is preferably 0.3 mmol / g or less, and particularly preferably 0. It is 1 mmol / g or less. As a result, the decrease in the molecular weight of the fine fibrous cellulose is suppressed, and the thickening effect in the solvent can be maintained for a long period of time. If the carbonyl group exceeds 0.5 mmol / g, there is a risk that agglutination may occur due to long-term storage and the viscosity may decrease significantly with the passage of time. As the reducing agent used in the reduction reaction, general ones can be used, but LiBH ₄ , NaBH ₃ CN, and NaBH ₄ are preferable. Among them, NaBH ₄ is particularly preferable from the viewpoint of cost and availability.

The amount of the reducing agent for reducing cellulose converted into a substituent having a carboxyl group is preferably in the range of 0.1 to 20% by weight, particularly preferably in the range of 3 to 10% by weight, as a reference. The reaction conditions are room temperature or a temperature slightly higher than room temperature, and the reaction is carried out for 10 minutes to 10 hours, preferably 30 minutes to 2 hours.

The total content of carbonyl groups (aldehyde group and ketone group) is measured by the semicarbazide method, for example, as follows. That is, first, exactly 50 ml of a 3 g / l aqueous solution of semicarbazide hydrochloride adjusted to pH = 5 with a phosphate buffer solution is added to the dried sample, the sample is sealed, and the mixture is shaken for 2 days. Then, 10 ml of this solution is accurately collected in a 100 ml beaker, 25 ml of 5N sulfuric acid and 5 ml of a 0.05 N potassium iodate aqueous solution are added, and the mixture is stirred for 10 minutes. Then, 10 ml of a 5% potassium iodide aqueous solution was added and immediately titrated with a 0.1 N sodium thiosulfate solution using an automatic titrator, and the amount of carbonyl group in the sample was determined according to the following formula based on the titration amount. Can be sought. Semicarbazide reacts with an aldehyde group or a ketone group to form a Schiff base (imine), but does not react with a carboxyl group. Therefore, it is considered that only the amount of the carbonyl group can be quantified by the above measurement.

<Process (2)>
In the step (2), the cellulose fibers after the above treatment are washed with an acid to convert the carboxyl group introduced in the above step (1) into an acid type, and the carboxyl group introduced in the above step (1) is appropriately purified by repeating filtration and washing with water, and then a centrifuge. This is a step of performing solid-liquid separation by means of the like, and then repeatedly washing the cellulose with an organic solvent to replace the solvent with an organic solvent from water.

(acid)
The type of acid is not particularly limited as long as the aqueous dispersion of cellulose fiber can be maintained acidic, and the above acid is an inorganic acid such as hydrochloric acid, nitrate, sulfuric acid, phosphoric acid, acetic acid, hydrogen peroxide, citric acid, and malic acid. , Lactic acid, adipic acid, sebacic acid, sodium sebacate, stearic acid, maleic acid, succinic acid, tartrate acid, fumaric acid, gluconic acid and other organic acids can be used. Hydrochloric acid is preferably used from the viewpoint of avoiding deterioration and damage of cellulose fibers due to acid and easiness of waste liquid treatment.

(Organic solvent)
The organic solvent is not particularly limited. For example, methanol, ethanol, isopropyl alcohol, 2-butanol, 1-pentanol, octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, stearyl alcohol, glycerin, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, Alcohols such as propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, 2-methyl-1-propanol glycerin, acetic acid, propionic acid, capric acid, capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, stea, olein Carbodies such as acids, linolenic acids, lactic acids, benzoic acids, succinic acids, maleic acids and fumaric acids, hydrocarbons such as hexane, heptane, octane, decane and liquid paraffin, aromatics such as toluene, xylene, ethylbenzene and naphthalene. Hydrocarbons, dimethylsulfoxide, dimethylformamide, dimethylacetamide, acetanylide and other amides, acetone, methylethylketone, diethylketone, methylisobutylketone, cyclohexanone, benzophenone and other ketones, methylene chloride, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene Halogens such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and other carbonates, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl butyrate, di2-ethylhexyl adipate, diisononyl adipate, diisodecyl adipate , Di2-ethylhexyl sebacate, di2-ethylhexyl azelaine, 4-cyclohexene-1,2-dicarboxylic acid bis (2-ethylhexyl),
Tricresyl phosphate, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester and other esters, polyethylene glycol, polytetramethylene oxide, polyoxyethylene alkyl ether and the like. Polyethers, silicone oils such as polydimethylsiloxane, dimethylsulfoxide, acetonitrile, propionitrile, ester oil, light oil, kerosene, crude oil, salad oil, soybean oil, castor oil, triglyceride, polyisoprene, fluorine-modified oil, etc. can give. These may be used alone or in combination of two or more. Further, instead of the organic solvent, a matrix resin described later, a solution obtained by diluting the matrix resin with an organic solvent, or a monomer of the matrix resin can also be used.

<Process (3)>
The step (3) is a step of adding the polyether amine represented by the above formula (1) to the oxidized cellulose after the substitution of the dispersion medium. As a result, the polyether amine represented by the above formula (1) is bonded to the carboxyl group of the above-mentioned oxidized cellulose, and the cellulose is made into a lipophilic oil. The reaction is carried out in the organic solvent.

<Process (4)>
The step (4) is a step of nano-defibrating the cellulose fibers after oil-forming in an organic solvent. Examples of the disperser used for the nano-defibration include a homomixer under high-speed rotation, a high-pressure homogenizer, an ultra-high-pressure homogenizer, an ultrasonic dispersion treatment, a beater, a disc-type refiner, a conical-type refiner, a double-disc-type refiner, and a grinder. By using a powerful and beating ability device such as, it becomes possible to make the device finer, and more efficient and advanced downsizing becomes possible. As the disperser, for example, a screw type mixer, a paddle type mixer, a disper type mixer, a turbine type mixer, or the like may be used.

[Matrix resin]
The matrix resin that can be suitably used in the present invention is not particularly limited as long as it can be used as an adhesive, and may be a monomer, an oligomer, or a polymer, and the polymer is a homopolymer. It may be a copolymer or a copolymer. Further, these may be used alone or in combination of a plurality of types.

The matrix resin is not particularly limited, and examples thereof include a polycondensation type resin, a polyaddition polymerization type resin, an addition condensation type resin, and an addition polymerization type resin, and among these, the weight is heavy from the viewpoint of compatibility with fine fibrous cellulose. Addition polymerization type resin and addition polymerization type resin are preferable.

Examples of the polyaddition polymerization resin include urethane resin, epoxy resin, aldehyde resin, and ketone resin.

Examples of the addition polymerization resin include acrylic resins, vinyl acid acid resins, vinyl chloride resins, vinylidene chloride resins and hydrocarbon resins, and copolymers thereof. Examples of the acrylic resin include acrylic resins such as polyacrylic acid ester and polymethacrylic acid ester, and copolymers thereof. Examples of the vinyl acid acid resin include an acrylic-styrene copolymer, an acrylic-vinyl acetate copolymer, an acrylic-vinyl chloride copolymer, an acrylic-ethylene copolymer, a polyvinyl acetate, and a vinyl acetate-vinyl acetate copolymer. , Vinyl acetate-ethylene copolymer, vinyl acetate-styrene copolymer and the like. Examples of the vinyl chloride resin include polyvinyl chloride, a vinyl chloride-acrylic copolymer, a vinyl chloride-ethylene copolymer, and a vinyl chloride-styrene copolymer. Examples of the hydrocarbon resin include polyethylene, polypropylene, polybutadiene, chloroprene, polystyrene, polyisobutylene, styrene-butadiene copolymer, polyacrylonitrile, acrylonitrile-butadiene copolymer, fluororesin, and silicone resin. In addition to these, synthetic resins modified with inorganic components can also be used, and examples thereof include ceramic-modified fluororesins, ceramic-modified urethane resins, and ceramic-modified acrylic resins. In addition, composite resins containing two or more different types of polymers in the particles can also be used, and urethane / acrylic, epoxy / acrylic, silicone / acrylic, polyester / acrylic, fluororesin / acrylic, colloidal silica / acrylic, and nitrocellulose / Examples include acrylic, melamine resin / acrylic, etc.

Examples of the polycondensation resin include amide resin, imide resin, alkyd resin, phthalic acid resin, fatty acid-modified phthalic acid resin, phenol-modified phthalic acid resin, unsaturated polyester resin, and polycarbonate.

Examples of the addition condensation resin include a phenol resin, a urea resin, and a urea melamine resin.

The solid content concentration of the fine fibrous cellulose in the adhesive composition of the present invention is 0.05% by mass or more and 3.0% by mass or more from the viewpoint of handleability and thickening with respect to 100% by mass of the total amount of the matrix resin and the fine cellulose. The range of mass% is preferable, and the range of 1.0 mass% or more and 2.0 mass% or less is more preferable.

[Other additives]
The adhesive composition of the present invention may contain various conventionally known additives depending on its use, for example, an antioxidant, a colorant, a flame retardant, an antioxidant, a polymerization initiator, and polymerization. Prohibition agents, UV absorbers, antistatic agents, lubricants, mold release agents, defoaming agents, leveling agents, light stabilizers (eg, hindered amines, etc.), antioxidants, conductivity-imparting agents, slidability-imparting agents, surfactants Examples thereof include activators, catalysts, curing accelerators, inorganic fillers, organic fillers and the like. These additives can be added in the above steps (2) to (4), but it is better to add them after adjusting the adhesive composition described later, because it can be adjusted according to the application required as an adhesive. Is preferable.

In addition, a non-reactive solvent can be added to the adhesive composition of the present invention, if necessary. Examples of the non-reactive solvent include aliphatic hydrocarbon solvents such as hexane and mineral spirit; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ester solvents such as butyl acetate; alcohol solvents such as methanol and butanol. Solvents: Aprotic polar solvents such as dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone and the like. These solvents may be used alone or in combination of two or more.

[Adhesive composition adjustment method]
The adhesive composition of the present invention can be prepared by uniformly kneading the above-mentioned cellulose nanofibers, resin, and various additive components as required. Examples of the kneading machine used at this time include a dispenser, a planetary mixer, a kneader, a Henschel mixer, a roll, an extruder and the like. Further, the produced adhesive composition can be applied to the substrate to be adhered by a usual method, for example, a method such as spraying, a sealer gun, or a brush coating.

Examples will be described together with comparative examples and the like. However, the present invention is not limited to these examples. In the example, "%" means a mass standard unless otherwise specified.

First, prior to Examples and Comparative Examples, cellulose fibers A1 to A4 for Examples and cellulose fibers A'1 and A'2 for Comparative Examples were prepared according to the following Production Examples 1 to 6.

[Production Example 1: Preparation of Cellulose Fiber A1 (for Examples)]
To 2 g of coniferous pulp, 150 ml of water, 0.25 g of sodium bromide, and 0.025 g of TEMPO are added, and the mixture is sufficiently stirred and dispersed. The amount of sodium hypochlorite was adjusted to 5.2 mmol / g, and the reaction was started. Since the pH decreases as the reaction progresses, the reaction was carried out while dropping a 0.5 N sodium hydroxide aqueous solution so as to maintain the pH at 10 to 11 until no change in pH was observed (reaction time: 120 minutes). .. After completion of the reaction, after neutralization by adding 0.1N hydrochloric acid, solid-liquid separation was performed with a centrifuge, and pure water was added to adjust the solid content concentration to 4%. Then, the pH of the slurry was adjusted to 10 with a 24% NaOH aqueous solution. The temperature of the slurry was set to 30 ° C., 0.2 mmol / g of sodium borohydride was added to the cellulose fibers, and the mixture was reacted for 2 hours for reduction treatment. After the reaction, 0.1N hydrochloric acid was added to neutralize the mixture, and the mixture was purified by repeating filtration and washing with water to obtain cellulose fiber A1.

[Production Example 2: Preparation of Cellulose Fiber A2 (for Examples)]
Cellulose fiber A2 was obtained according to the method for preparing cellulose fiber A1 except that the amount of the sodium hypochlorite aqueous solution added was 12.0 mmol / g with respect to 1.0 g of the pulp.

[Production Example 3: Preparation of Cellulose Fiber A3 (for Examples)]
100 g of softwood pulp was placed in a mixture of 435 g of isopropanol (IPA), 65 g of water and 9.9 g of NaOH, and the mixture was stirred at 30 ° C. for 1 hour. 23.0 g of an IPA solution of 50% monochloroacetic acid was added to this slurry system, the temperature was raised to 70 ° C., and the reaction was carried out for 1.5 hours. The obtained reaction product was washed with 80% methanol, then replaced with methanol and dried to obtain cellulose fibers A3.

[Production Example 4: Adjustment of Cellulose Fiber A4 (for Examples)]
20 g of urea, 12 g of sodium dihydrogen phosphate dihydrate, and 8 g of disodium hydrogen phosphate were dissolved in 20 g of water to prepare a phosphorylating agent, and 20 g of coniferous pulp (LBKP) crushed with a household mixer was kneaded. The mixture was spray-sprayed with stirring to obtain a phosphate-impregnated pulp. Next, the phosphorylated pulp was obtained by heat-treating the phosphorylated pulp in a blower dryer equipped with a damper heated to 140 ° C. for 60 minutes. Water was added to the obtained phosphorylated pulp to adjust the solid content concentration to 2%, and the mixture was stirred, mixed and uniformly dispersed, and then the operations of filtration and dehydration were repeated twice. Next, water was added to the obtained recovered pulp to bring the solid content concentration to 2%, and a 1N aqueous sodium hydroxide solution was added little by little with stirring to obtain a pulp slurry having a pH of 12 to 13. Subsequently, this pulp slurry was filtered and dehydrated, water was further added, and the operations of filtration and dehydration were repeated twice, and then the pulp slurry was replaced with methanol and dried to obtain cellulose fibers A4.

[Production Example 5: Preparation of Cellulose Fiber A'1 (for Comparative Example)]
50 g of softwood bleached kraft pulp (NBKP) was dispersed in 4950 g of water to prepare a dispersion having a pulp concentration of 2%. This dispersion was treated with Serendipitter MKCA6-3 (manufactured by Masuyuki Sangyo Co., Ltd.) 30 times to obtain cellulose fiber A'1.

[Production Example 6: Preparation of Cellulose Fiber A'2 (for Comparative Example)]
Regenerated cellulose was used instead of the raw material coniferous pulp, and the amount of sodium hypochlorite aqueous solution added was 27.0 mmol / g with respect to 1.0 g of regenerated cellulose. Cellulose fiber A'2 was prepared accordingly.

Using the above cellulose fibers, each characteristic was evaluated according to the following evaluation method.

<Crystal structure>
The diffraction profile of the cellulose fiber is measured using an X-ray diffractometer (RINT-Ultima3, manufactured by Rigaku Co., Ltd.), and is typical of two positions, 2 theta = 14 to 17 ° and 2 theta = 22 to 23 °. If a typical peak is seen, the crystal structure (type I crystal structure) is "yes".
When no peak was seen, it was evaluated as "none".

<Measurement of carboxyl group amount>
60 ml of an aqueous cellulose dispersion in which 0.25 g of the above cellulose fibers was dispersed in water was prepared, the pH was adjusted to about 2.5 with a 0.1 M aqueous hydrochloric acid solution, and then a 0.05 M aqueous sodium hydroxide solution was added dropwise. , Electrical conductivity was measured. The measurement was continued until the pH reached 11. The amount of carboxyl groups was determined from the amount of sodium hydroxide (V) consumed in the neutralization step of the weak acid in which the change in electrical conductivity was gradual according to the following formula.

<Measurement of carboxymethyl group amount>
The above cellulose fibers are prepared in a 0.6 mass% slurry, and a 0.1 M hydrochloric acid aqueous solution is added to adjust the pH to 2.4, and then a 0.05 N sodium hydroxide aqueous solution is added dropwise to bring the electrical conductivity until the pH reaches 11. The amount of carboxyl groups can be measured from the amount of sodium hydroxide consumed in the neutralization step of a weak acid whose electrical conductivity changes slowly, and can be calculated using the following formula.

<Measurement of phosphate group amount>
The cellulose fibers were diluted with ion-exchanged water so as to have a solid content concentration of 0.2% by mass, and then treated with an ion-exchange resin and titrated with an alkali. In the treatment with an ion exchange resin, a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) with a volume of 1/10 is added to a slurry containing 0.2 mass% fine cellulose fibers and shaken for 1 hour. Was done. Then, it was poured onto a mesh having a mesh size of 90 μm to separate the resin and the slurry. In the titration using alkali, the change in the value of electrical conductivity exhibited by the aqueous dispersion was measured while adding a 0.1 N aqueous sodium hydroxide solution to the aqueous dispersion of fine cellulose fibers after ion exchange. That is, the amount of alkali [mmol] added until the value of electrical conductivity became the smallest was divided by the solid content [g] in the slurry to be titrated to obtain the amount of phosphoric acid groups [mmol / g].

<Measurement of carbonyl group amount>
Approximately 0.2 g of the above-mentioned cellulose fiber was precisely weighed, and exactly 50 ml of a 3 g / l aqueous solution of semicarbazide hydrochloride adjusted to pH = 5 with a phosphate buffer solution was added thereto, and the mixture was sealed and shaken for 2 days. Next, 10 ml of this solution was accurately collected in a 100 ml beaker, 25 ml of 5N sulfuric acid and 5 ml of a 0.05 N potassium iodate aqueous solution were added, and the mixture was stirred for 10 minutes. Then, 10 ml of a 5% potassium iodide aqueous solution was added, and the sample was immediately titrated with a 0.1 N sodium thiosulfate solution using an automatic titrator, and the amount of carbonyl group (aldehyde) in the sample was determined according to the following formula based on the titration amount. The total content of the group and the ketone group) was determined.

[Example 1]
Methanol was added to the cellulose fiber A1 and filtered, and washing with methanol was repeated to replace the water contained in the cellulose fiber with methanol. Then, methanol and an equal amount of polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) equal to the amount of carboxyl groups of the cellulose fiber A1 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer is used. (Starburst, manufactured by Sugino Machine Limited) was used to treat once at a pressure of 100 MPa to obtain a gel-like composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the above gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Then, bisphenol A and dicyandiamide (Ajinomoto Co., Inc., Amicure AH-154) were added as a curing agent, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece.

Using the above gel-like composition, adhesive composition, and test piece, each characteristic was evaluated according to the following evaluation method.

<Measurement of number average fiber diameter and aspect ratio>
The number average fiber diameter and fiber length of the cellulose fibers of the gel-like composition were observed using a transmission electron microscope (TEM, JEM-1400 manufactured by JEOL Ltd.). That is, from a TEM image (magnification: 10000 times) in which each cellulose fiber was cast on a hydrophilicized carbon film-coated grid and then negatively stained with 2% uranyl acetate, the number average fiber diameter was increased according to the method described above. , And the fiber length were calculated. Furthermore, using these values, the aspect ratio was calculated according to the following formula.

<Evaluation of dispersion stability>
The adhesive composition was transferred to a test tube and allowed to stand overnight. The dispersibility was evaluated as follows based on the dispersed state of the cellulose fibers in the test tube.
◯: Cellulose fibers were uniformly dispersed in the adhesive composition.
X: Cellulose fibers were settled in the adhesive composition.

<Evaluation of adhesive strength>
Using a universal testing machine (manufactured by Instron Japan Co., Ltd., type 5581), the above test piece was set to 2.5 mm / min. , 23 ° C. and 80 ° C., and the tensile shear adhesive strength was measured. When <evaluation of dispersion stability> is "x", it was decided not to evaluate the adhesive strength.

<Evaluation of heat resistance>
From the tensile shear adhesive strength (S23) obtained by the measurement at 23 ° C. and the tensile shear adhesive strength (S80) obtained by the measurement at 80 ° C., the rate of decrease in the tensile shear adhesive strength [% ] Was calculated. From the calculated shear adhesion strength reduction rate, evaluation was made based on the following criteria. In the above <evaluation of dispersion stability>, when the cellulose fibers are settled, the heat resistance is not evaluated.

◎：９５％以上
○：９５％未満９０％以上
△：９０％未満８０％以上
×：８０未満

⊚: 95% or more ○: less than 95% 90% or more Δ: less than 90% 80% or more ×: less than 80

[Examples 2, 5 to 9, Comparative Example 1]
The concentration of the cellulose fiber, the concentration of the modifier, the concentration of the matrix resin, and the concentration of the curing agent in the adhesive composition were changed as shown in Table 2 below. .. A gel-like composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1 except for the above, and each characteristic was evaluated.

[Example 3]
Water was added to the cellulose fiber A3 to dilute it to a solid content of 1%, and T.I. K. While stirring with a homomixer (manufactured by PRIMIX Corporation) at 8000 rpm for 10 minutes, 1N hydrochloric acid was added until the pH of the solution became 2. Then, it was filtered, sufficiently washed with water, and repeatedly washed with methanol to prepare an acid-type cellulose fiber A3 in which the solvent was replaced with methanol. To the acid-type cellulose fiber A3, methanol and a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) in an amount equal to the amount of the carboxyl group of the cellulose fiber A3 were added, diluted to 2%, and a high-pressure homogenizer (Sugino) was added. A gel-like composition was obtained by treating once with a pressure of 100 MPa using Starburst (manufactured by Machine Limited). Modified bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with modified bisphenol A. Then, bisphenol A and dicyandiamide (Ajinomoto Co., Inc., Amicure AH-154) were added as a curing agent, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece. Using the gel-like composition, the adhesive composition and the test piece, each characteristic was evaluated by the same evaluation method as in Example 1.

[Example 4]
Water was added to the cellulose fiber A4 to dilute it to a solid content of 1%, and T.I. K. While stirring with a homomixer (manufactured by PRIMIX Corporation) at 8000 rpm for 10 minutes, 1N hydrochloric acid was added until the pH of the solution became 2. Then, the mixture was filtered, sufficiently washed with water, and repeatedly washed with methanol to prepare an acid-type cellulose fiber A4 in which the solvent was replaced with methanol. To the acid-type cellulose fiber A4, methanol and a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) in an amount equal to the amount of the phosphate group of the cellulose fiber A4 were added, diluted to 2%, and a high-pressure homogenizer (high-pressure homogenizer). A gel-like composition was obtained by treating once with a pressure of 100 MPa using Sugino Machine Limited (Starburst). Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with modified bisphenol A. Then, bisphenol A and dicyandiamide (Ajinomoto Co., Inc., Amicure AH-154) were added as a curing agent, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece. Using the gel-like composition, the adhesive composition and the test piece, each characteristic was evaluated by the same evaluation method as in Example 1.

[Example 10]
Methanol was added to the cellulose fiber A2 and filtered, and washing with methanol was repeated to replace the water contained in the cellulose fiber with methanol. Then, methanol and an equal amount of polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) equal to the amount of carboxyl groups of the cellulose fiber A1 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer is used. (Starburst, manufactured by Sugino Machine Limited) was used to treat once at a pressure of 100 MPa to obtain a gel-like composition. Toluene was added to the gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with toluene. Then, toluene and the polyvinyl acetate shown in Table 2 below (Denkasacanol SN-10, manufactured by Denki Kagaku Kogyo Co., Ltd.) were further added to obtain T.I. K. By stirring with a homomixer (manufactured by PRIMIX Corporation) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration and the matrix resin concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece. Using the gel-like composition, the adhesive composition, and the test piece, each characteristic was evaluated by the same evaluation method as in Example 1.

[Example 11]
Methanol was added to the cellulose fiber A2 and filtered, and washing with methanol was repeated to replace the water contained in the cellulose fiber with methanol. Then, methanol and an equal amount of polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) equal to the amount of carboxyl groups of the cellulose fiber A2 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer is used. (Starburst, manufactured by Sugino Machine Limited) was used to treat once at a pressure of 100 MPa to obtain a gel-like composition. An acrylic monomer (Metal Lock Y610A, manufactured by Cemedine Co., Ltd.) was added to the gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with the acrylic monomer. After that, an acrylic monomer and a curing agent (Metal Lock Y610B manufactured by Cemedine Co., Ltd.) were added as a matrix resin, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend, and the adhesive composition was cured by leaving it at room temperature for 1 hour to obtain a test piece. Using the gel-like composition, the adhesive composition, and the test piece, each characteristic was evaluated by the same evaluation method as in Example 1.

[Example 12]
Methanol was added to the cellulose fiber A2 and filtered, and washing with methanol was repeated to replace the water contained in the cellulose fiber with methanol. Then, methanol and an equal amount of polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) equal to the amount of carboxyl groups of the cellulose fiber A2 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer is used. (Starburst, manufactured by Sugino Machine Limited) was used to treat once at a pressure of 100 MPa to obtain a gel-like composition. A nitrile rubber-based adhesive (manufactured by 3M, solvent-based adhesive EC776) was added to the gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.). After that, MEK was added, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX Corporation) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration and the matrix resin concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend, and the adhesive composition was cured by leaving it at room temperature for 1 hour to obtain a test piece.

[Example 13]
Methanol was added to the cellulose fiber A1 and filtered, and washing with methanol was repeated to replace the water contained in the cellulose fiber with methanol. Then, methanol and an equal amount of polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) equal to the amount of carboxyl groups of the cellulose fiber A1 are added to dilute the cellulose fiber concentration to 2%, and a high-pressure homogenizer is used. (Starburst, manufactured by Sugino Machine Limited) was used to treat once at a pressure of 100 MPa to obtain a gel-like composition. A polyol (Aimflex 318A, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was added to the gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with the polyol. Then, a polyol as a main agent and a polyisocyanate (Aimflex 318B manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as a curing agent were added, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 80 ° C. for 2 hours to cure the adhesive composition to obtain a test piece. Using the gel-like composition, the adhesive composition, and the test piece, each characteristic was evaluated by the same evaluation method as in Example 1.

[Examples 14 and 15]
Cellulose fiber A1 is used as cellulose fiber A2, and a modifier, a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070), is used as a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) / aliphatic amine shown in Table 2 below. A gel-like composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1 except that the mixture was changed to a mixed solution (50/50 in molar ratio), and each characteristic was evaluated.

[Example 16]
Cellulose fiber A1 is used as cellulose fiber A2, and a modifier, a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070), is used as a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) / aliphatic amine shown in Table 2 below. A gel-like composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1 except that the mixture was changed to a mixed solution (molar ratio 75/25), and each characteristic was evaluated.

[Example 17]
Cellulose fiber A1 is used as cellulose fiber A2, and a modifier, a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070), is used as a polyether amine (manufactured by HUNTSMAN, JEFFAMINE M-2070) / aliphatic amine shown in Table 2 below. A gel-like composition, an adhesive composition, and a test piece were prepared in the same manner as in Example 1 except that the mixture was changed to a mixed solution (molar ratio 25/75), and each characteristic was evaluated.

[Comparative Example 2]
Methanol was added to the cellulose fiber A3, filtered, and washed repeatedly with methanol to replace the water contained in the cellulose fiber with methanol. Then, methanol was further added to dilute it to 2%, and the mixture was treated once with a high-pressure homogenizer (manufactured by Sugino Machine Limited, Starburst) at a pressure of 100 MPa to obtain a gel-like composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the above gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Then, bisphenol A was added as a main agent and dicyandiamide (Ajinomoto Co., Inc., Amicure AH-154) was added as a curing agent, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. Using the gel-like composition and the adhesive composition, each characteristic was evaluated by the same evaluation method as in Example 1.

[Comparative Example 3]
Methanol was added to the cellulose fiber A'1, and the mixture was filtered and washed repeatedly with methanol to replace the water contained in the cellulose fiber with methanol as a solvent to obtain a gel-like composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the gel-like composition, and the mixture was added.
The dispersion solvent was replaced with bisphenol A by distilling off methanol using a rotary evaporator (manufactured by Tokyo Rikaki Co., Ltd.). Then, bisphenol A was added as a main agent and dicyandiamide (Ajinomoto Co., Inc., Amicure AH-154) was added as a curing agent, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. Using the gel-like composition and the adhesive composition, each characteristic was evaluated by the same evaluation method as in Example 1.

[Comparative Example 4]
Water was added to the cellulose fiber A'2 to dilute it, and freeze-drying was performed. To the lyophilized product, methanol and an equal amount of polyether amine (JEFFAMINE M-2070, manufactured by HUNTSMAN) equal to the amount of carboxyl groups of the above-mentioned cellulose fiber A'2 were added to dilute to 2%, and a high-pressure homogenizer (Sugino Machine Limited) was added. , Starburst) was used to treat once at a pressure of 100 MPa to obtain a gel-like composition. Bisphenol A (manufactured by DIC, EPICLON 850S) was added to the above gel-like composition, and methanol was distilled off by a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) to replace the dispersion solvent with bisphenol A. Then, bisphenol A was added as a main agent and dicyandiamide (Ajinomoto Co., Inc., Amicure AH-154) was added as a curing agent, and T.I. K. By stirring with a homomixer (manufactured by PRIMIX) at 8000 rpm for 10 minutes, an adhesive composition in which the cellulose fiber concentration, the modifier concentration, the matrix resin concentration, and the curing agent concentration were adjusted as shown in Table 2 was obtained. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece. Using the gel-like composition, the adhesive composition, and the test piece, each characteristic was evaluated by the same evaluation method as in Example 1.

[Comparative Example 5].
An adhesive composition was obtained in which the bisphenol A concentration was adjusted to 94.6% (DIC, EPICLON 850S) and the dicyandiamide (Ajinomoto, Amicure AH-154) concentration was adjusted to 5.4%. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece. Each characteristic was evaluated using the test piece by the same evaluation method as in Example 1.

[Comparative Example 6]
The resin shown in Table 2 below was added to toluene to obtain an adhesive composition having a resin concentration of 20%. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 150 ° C. for 1 hour to cure the adhesive composition to obtain a test piece. Each characteristic was evaluated using the test piece by the same evaluation method as in Example 1.

[Comparative Example 7].
An adhesive composition was obtained in which the concentration of the acrylic monomer was adjusted to 50% (Cemedine Co., Ltd., Metal Lock Y610A) and the concentration of the curing agent (Cemedine Co., Ltd., Metal Lock Y610B) was adjusted to 50%. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend, and the adhesive composition was cured by leaving it at room temperature for 1 hour to obtain a test piece. Each characteristic was evaluated using the test piece by the same evaluation method as in Example 1.

[Comparative Example 8]
A nitrile rubber adhesive (3M, solvent-based adhesive EC776) is cured by using a cold-rolled steel sheet with a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm as an adherend and leaving it at room temperature for 1 hour. And obtained a test piece. Each characteristic was evaluated using the test piece by the same evaluation method as in Example 1.

[Comparative Example 9]
An adhesive composition was obtained in which the polyol concentration was adjusted to 59% and the polyisocyanate concentration was adjusted to 41%. A cold-rolled steel sheet having a thickness of 1.6 mm, a width of 25 mm, and a length of 100 mm was used as an adherend and heated at 80 ° C. for 2 hours to cure the adhesive composition to obtain a test piece. Each characteristic was evaluated using the test piece by the same evaluation method as in Example 1.

※1 ＨＵＮＴＳＭＡＮ社製、ＪＥＦＦＡＭＩＮＥ Ｍ−２０９５
※2 ＨＵＮＴＳＭＡＮ社製、ＪＥＦＦＡＭＩＮＥ Ｍ−２００５
※3 セメダイン社製、メタルロックＹ６１０Ａ
※4 セメダイン社製、メタルロックＹ６１０Ｂ
※5 溶剤であるトルエンを除いたときの濃度
※6 数平均繊維径が１ｎｍ以下であるため測定不可。

* 1 JEFFAMINE M-2095 manufactured by HUNTSMAN
* 2 JEFFAMINE M-2005 manufactured by HUNTSMAN
* 3 Metal Lock Y610A manufactured by Cemedine Co., Ltd.
* 4 Metal Lock Y610B manufactured by Cemedine Co., Ltd.
* 5 Concentration excluding toluene as a solvent * 6 Cannot be measured because the number average fiber diameter is 1 nm or less.

From the results shown in Table 2 above, the adhesive compositions of Examples were obtained with better results in terms of adhesive strength and heat resistance than the adhesive compositions of the resin alone of Comparative Examples 5 to 9. On the other hand, since the adhesive compositions of Comparative Examples 1 and 2 lack the hydrophobicity of the modifier, and the adhesive composition of Comparative Example 3 does not have the modifier, the cellulose fibers are contained in the solvent. It aggregated and did not give good results in terms of dispersion stability. In the adhesive composition of Comparative Example 4, the cellulose fibers were dispersed in the solvent without agglomeration, but the adhesive strength and heat resistance were not improved because the cellulose fibers did not have a crystal structure.

Since the adhesive composition of the present invention has excellent heat resistance and adhesive strength, it is widely used in aerospace fields, electronics, civil engineering, construction, and other technical fields, as well as in automobiles and automobiles. be able to.

Claims (5)

An adhesive composition containing fine fibrous cellulose and a matrix resin satisfying the following conditions (A) to (E), wherein the fine fibrous cellulose further satisfies the following condition (F). A characteristic adhesive composition.
(A) Number average fiber diameter is 2 nm or more and 500 nm or less (B) Average aspect ratio is 10 or more and 1000 or less (C) Cellulose type I crystal structure (D) Anionic functional group (E) Above (D) A polyether amine represented by the following formula (1) is bonded to a part of the above-mentioned anionic functional group.

[In the above formula (1), R ¹ , R ² , and R ³ represent linear or branched alkyl groups having 1 or more and 10 or less carbon atoms, or hydrogen atoms, and n1, n2, and n3 are 0 or more and 80 or less, respectively. (N1 + n2 + n3) indicates 10 or more and 240 or less, AO indicates an oxyalkylene group having 2 or more and 4 or less carbon atoms, the average value of x is 0.5 or more and 1 or less, and the average value of y and z is 0 or more and 1 The following is shown. ]
(F) A polyether amine represented by the general formula (1) and an amine compound represented by the following general formula (2) are bonded to a part or all of the anionic functional groups described in the above (D).

[In the above formula (2), R ⁴ , R ⁵ , and R ⁶ represent a linear or branched alkyl group having 2 or more and 18 or less carbon atoms, or a hydrogen atom. ] The adhesive composition according to claim 1, wherein the anionic functional group of the fine fibrous cellulose is a carboxyl group. Claim 1 or 2 characterized in that the matrix resin contains one kind or two or more kinds selected from a polycondensation type resin, a polyaddition polymerization type resin, an addition condensation type resin, and an addition polymerization type resin. The adhesive composition according to. The adhesive composition according to any one of claims 1 to 3, wherein the matrix resin contains an epoxy resin, a urethane resin, an acrylic resin, a vinyl acid acid resin, and a hydrocarbon resin. .. The adhesive composition according to any one of claims 1 to 4, wherein the solid content of the fine fibrous cellulose is in the range of 0.05% by mass or more and 3.0% by mass or less.